Pneumatic strap sealer



wlw-lul minimum 2 Sheets-Sheet l S. W. TREAT PNEUMATIC STRAP SEALER Filed May l0 1926 .vil

June 17, 1930.

June 17, 1930. 5 W, TREAT PNEUMATIC STRAP SEALER Filed May l0 1926 2 Sheets-Sheet 2 Patented June 17, 1930' UNITED STATES SIDNEY W. TREAT, 0F CHICAGO, ILLINOIS, ASSIGNOR, :BY

MESNE ASSIGNMENTS, T0

SIGNODE STEEL STRAPPING COMPANY, A CORPORATION 0F ILLINOIS PNEUMATIC STRAP SEALER Application filed May 10, 1926. Serial No. 107,917.

My invention relates generally to tools for joining metallic straps such as are used in strapping boxes, bales and similar containers. It relates more particularly to a pneumatic operated device of this kind which is portable and may be manually positioned over the straps to be sealed together and pneumatically operated to form the sea It is an object of my invention to provide a pneumatic sealer which is simple in construction, which is light in weight and which may be easily controlled.

A further object is to provide a pneumatie sealer in whichthe jaws are pneumatically operated both to form the seal and to loosen the jaws after the seal has been formed.

Other objects will appear from the following description, reference being had to the accompanying drawings in which:

Figure l is an elevation of the tool with a portion of the case broken away to show the interior construction;

Figure 2 is vertical section taken on the line 2-2 of Figure 1, the cylinder having been moved to its upper position;

Figure v3 is a horizontal cross section taken on the line 3 3 of Figure 1;

Figure 4 is a horizontal sectional view taken on` the line 4.--4 of Figure 2;

Figure 5 is a similar sectional view taken on the line 5 5 of Figure 2, and

Figure 6 is a perspective View of one of the forming jaws and its operating link.

According to my present invention the 'source of power is adapted to be used both for applying and for loosening the tool, the source of power being controlled by a trigger or similar valve operating member. The valve operating member is preferably located adjacent the handle of the tool so that while the hand controls the tool as a whole, a finger or thumb can control the power admitted to it. A convenient source of power is compressed air, in which case the power controlling means may advantageously be a reciprocatory plunger valve, cylindrical in form.

While I have Shown and Will describe my invention as being pneumatically operated, 1t will be apparent that it may be slightly modified so as to be adapted to be operated by steam or hydraulic pressure, and that some of the features of my invention ma be employed in a sealing tool which is operated by an electric motor or other equivalent source of power.

The main working parts of the tool are enclosed in an aluminum casing formed in two similar parts 8 and 9 which are suitably secured together by bolts 11 passing through ears 12 in the halves of the casing. The lower ends of the casing halves are also held in position by a bolt 14: which also serves for other purposes as will be later described. The upper edges of the parts 8 and 9 of the casing are inwardly flanged as is best shown in Figure 2 and are secured to the central body portion or piston 15 by means of screws 16.

A cylinder 17 is vertically reciprocable relative to the body portion l5 and is provided with an annular ring 18 riveted at its upper edge, to which ring a suitable annular flexible washer 19 is secured by a metallic backing ring 20. The parts 18, 19 and 20 may be held together by means of rivets or screws 21. A piston head 22 is secured to the lower end of the body portion by means of the bolts 23 and has attached thereto an annular flexible washer 24: which is similar to the washer 19 in construction and isv similarly secured to the piston head 22. A cup washer 24 is secured at the lower end of the body portion by means of a metallic backing disc 25 which is held to the piston by means of the bolts 23. A double seal is thus formed between the inside wall of the cylinder 17 and the outer wall of the body portion 15. As best shown in Figure 5, the body portion" is in the shape of a hollow cylinder having a diametrical bridged portion 15a in which verticalair ducts 26, 27, 28 and 29 are formed. A sliding valve 30 is adapted to be reciprocated in a cylindrical valve chamber 31 formed in the valve body 32. The valve body 32, as well as the handle 33, is secured to the body member by Screws 34, The

Cil

-. valve body in any suitable manner.

air from the tool.

valve is normally spring pressed to the left (Figure 2) by means of a compression coil spring which at one end abuts against a hose connection 36 which 1s screwed into the tapped end of the valve chamber 31, the other end bearing against the end of the valve 30. The right hand portion (Figure 2) of the valve 30 is axially radially drilled as shown in dotted lines of Figure 2 to form a passage 30a which is adapted to admit air to the valve chamber at the reduced portion 30b of the valve. The valve also has a second portion 30c of reduced diameter. The Valve body 32 has small ports 38, 39, 41 and 42 which register with the passages 28, 29, 26 and 27, respectively.v An exhaust passage 43 opens to the atmosphere through a suitable hole drilled in the handle 33, to permit the escape of The valve 30 which as has been pointed out is reciprocable in the valve body 32, its movement toward the left being limited by a stop 44 which engages a shoulder formed at the end of the valve. This stop may be secured to the end of lte e valve may be moved to the right (Figure 2) by means of the trigger 45 which is pivotally mounted in a slot in the handle upon a screw 46 fixed in the handle. The lower end 45 of the trigger is adapted to engage the end 30c which is of reduced diameter and passes through a hole formed in the stop 44. Upon the pressing of the trigger 45 it will be apparent that the valve 30 will be moved to the right (Figure 2) and its reduced portion 3()b will be brought opposite the port 39.

When tri ger 45 is pressed moving valve 30 to the rlght, the supply of compressed air entering through the coupling 36 will pass through the passage 30 formed at the right hand end of the valve, about reduced valve portion 30 through the port 39 and into the passage 29 to the lower end of the cylinder, thus causing the cylinder to move downwardly. The downward movement of the cylinder is limited by the contact of a boss 47, formed at its lower end, with a stop 48 which is fixed to the inside of the casing. During the downward movement of the cylinder air is permitted to escape from the ,chamber 51, between the body and the cylinder, through a drilled hole 52 leading from this chamber -to the passage 27 and hence through the port 42 and around the reduced portion 30c of the valve 30 and then to vthe atmosphere through the passage 43. Upon the release of the trigger the spring 35 will force the valve to its left-most position, (shown in Figure 2) in which the parts 39 and 42 are closed. In this position of the valve, air is admitted through the passage 3021 to the port 38, passage 28 and then through a hole 53 connecting the passage 28 with the chamber 51 to this chamber. Upon admission of the air to this chamber the cylinder will obviously be forced upwardly and the air in the chamber 49 will be exhausted through the passage 26, port 41, around the reduced portion 3()c of the valve 30 and hence to the atmosphere through the passage 43. It will thus be apparent that the cylinder will move downwardly upon depression of the trigger 45 and will again return to its original position upon the release of the trigger. This movement of the cylinder is utilized to operate the seal forming tools which are connected at thelower end of the cylinder, as will presently be described.

A pair of links 53 and 54, U shaped in cross section, are pivotally secured to the lugs 47 at the lower end of the cylinder by means of a pivot pin 55 which is secured against movement in the lugs by means of a pin 56.

Similar links 57 and 58 are pivotally connected to the links 53 and 54 by means of pins 59 and 61 respectively. These links are similarly shaped and are best shown in perspective in Fig. 6. Steel aws 62 and 62 have upwardly projecting lugs 63 and 63 which lie adjacent of the respective sides of the links 57 and 58 and are riveted or welded thereto. The lugs 63 and 63 have drilled holes 64 in register with the holes 65 formed at the ends of the links to permit passage of the bolt 14. The lower portions of the jaws 62 and 62 lie beneath the edges of the sides of the link 58. Hardened forming pins 66 fit in a drilled shouldered hole formed in the jaws 62 and 62. These pins are adapted to form the crimp in the strap seal, the straps and seal being held against upward movement by a U-shaped seat member 68 which is pivotally mounted on the bolt 14.

It will be apparent that upon downward movement of the cylinder 17 the links 53, 54, 57 and 58 will co-operate as a toggle and due to the great leverage, the jaws 62 will be forced together under considerable pressure to form the seal, the stop 48 secured to the casing 9 being adapted to limit the downward movement of the cylinder 17. Upon upward movement of the cylinder the jaws will be separated permitting the tool to be removed from the sealing straps.

The operation of the tool is as follows: The tool is placed with its jaws over the vends of the strap to be sealed and the trigger 45 momentarily depressed. The cylinder will thereupon be forced downwardly,

- bringing the jaws together to form the seal.

Upon release of the trigger the cylinder will be forced upwardly, separating the jaws and thus releasing the tool.

While the form of mechanism herein shown and described is admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not` intended to coniine the invention to the one form of embodiment herein disclosed, and it is susceptible of embodiment in various forms all coming within the scope of the claims which follow.

1. In a device of the class described, the combination of a piston, a reciprocable cylinder, reciprocable valve means for alternately admittin air to said cylinder on opposite sides o said piston, jaws adapted to form seals on metallic strappings operatively connected to said cylinder, and a casing completely surrounding said c linder, fixed relative to said piston, and orming a pivotal support for said jaws.

2. In a device of the class described, the combination of a piston, a cylinder reciprocable relative to said piston, means or admitting air under pressure to said cylinder to reciprocate said cylinder relative to said piston, a pair of links pivotally connected to such cylinder at a common pivot, a second pair of links pivotally connected atthe ends of said lirst pair and pivotally joined at their opposite extremities, a pair of seal-forming jaws secured to the ends of said second pair of links, and a casing completely surrounding said cylinder, fixed relative to said piston, and forming a support for said jaws.

3. In a device of the class described, the combination of a casing, a piston member secured thereto, a cylinder reciprocable relative to said piston, a valve for controlling the admission to and exhaust ofair from said cylinder, a stop secured to said casing for limiting the movement of said cylinder in one direction, a pair of sealing jaws pivotally mounted in said casing, and link mechanism connecting said cylinder with said jaws so that reciprocation of said cylinder will open and close said jaws.

4. In a device of the class described, the combination of a piston, a casing fixed relative to said piston, a reciprocable cylinder surrounding said piston, sealing means between said iston and cylinder, a head secured to said) piston and sealed in said cylinder, valve means for controlling the admission to and exhaust of air from said cylinder, a pair of jaws for joining metallic strap ends pivotally mounted in said casin and a link mechanism between said cy -nder and said jaws for opening and c osin said jaws upon reciprocation of said cylin er:

5. In a device of the class described, a piston, a casing fixed relative thereto, a head on said piston, a cylinder reciprocable relative to said piston, a valve mechanism for controlling the admission to and exhaust of air from said cylinder, jaws for joining metallic strap ends pivotally mounted in said casing, and a link mechanism operatively connecting said cylinder with said jaws.

6. In a device of the class described, a piston, a casing fixed relative thereto, a cylinder reciprocable relative to said piston, a head secured to said piston and forming a seal between said iston and cylinder, a packing ring securedp to said cylinder and contactlng said piston, a pair of jaws pivotally mounted in said casing, means operatively connecting said cylinder to said jaws, intake and exhaust ducts communicating with the space on opposite sides of said head respectively, a reciprocable valve when in one position adapted to admit air under pressure to the space on one side of said head and concurrently release the air from the opposite side of said head, and when in another position to release air from said first named side and admit air under pressure to second named side of said head, and trigger means for controlling the position of said valve.

7. A tool of the class described comprising a pair of jaws adapted to form seals on metallic strappings, force multlplying means associated with said jaws, pneumatic means, including a piston, a cylinder and a valve, for operating said force multiplyin means to open and close said jaws at wil and a casin completely surrounding said cylinder, fixed relative to said piston, and forming a pivotal support for said jaws.

8. In a device of the class described, a piston, a stem secured to said piston and having a handle rigid therewith, the displacement of said stem being large relative to the piston displacement, a manually operable air valve associated with said stem, a pair of inlet and a pair of discharge passageways in saidstem, one of each of said palrs extending to one side of said piston and the other of each of said pairs of passageways extending to the opposite side of .said piston, a cylinder reciprocable-relative to said piston, a packing between said cylinder and said stem, and sealing jaws o eratively connected to said cylinder and a apted to open and Y close upon reciprocation thereof.

` In witness whereof, I hereunto subscribe my name this 6th day of May, 1926.

- SIDNEY W. TREAT.

llO 

